Titre :
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Cationic oligonucleotides for DNA strand invasion and gene correction (abstract : congrès international de Myologie, 2005)
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contenu dans :
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Auteurs :
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Congrès international de myologie 2005 (International Congress of Myology 2005; 9-13 mai 2005; Nantes, France) ;
Pons B ;
Fraley A ;
Zuber G ;
Behr JP
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Type de document :
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Article
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Année de publication :
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2005
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Pages :
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p. 276
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Langues:
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Anglais
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Mots-clés :
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ADN
;
colloque
;
encapsulation
;
mutation génétique
;
nucléoside-nucléotide
;
protéine
;
thérapie génique
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Résumé :
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Communication n° 97 The basic concept behind gene therapy is to transfer a gene into the cell nucleus and thereby express a missing protein. An alternative to treat inherited and acquired genetic disorders is the use of small oligodeoxyribonucleotides (ODN) designed to target the genomic mutation in situ and correct it. This method is attractive because it may lead to permanent correction and allow the repaired gene to remain under endogenous regulation. ODN used for gene correction are homologous to the target sequence except for the point mutation. DNA repair machineries would eventually recognize the mismatch created by the specific hybridization of these ODN to the target gene and correct the chromosomal base by an excision/repair mechanism. However, the ability of native ODN to strand-invade chromosomal DNA is low. Thus, increase ODN affinity for duplex DNA is a key factor to enhance gene correction frequencies. Our approach to shift the mismatch-hybridization to a more favorable state is to minimize electrostatic repulsion between negatively charged phosphodiesters by adding positive charges. We therefore chose to conjugate cationic polypeptides to small single stranded oligodeoxyribonucleotides (ssODN). A series of polypeptides has been synthesized and crosslinked to the 5' end of a 15mer ssODN in order to obtain anionic, neutral and cationic ssODN. The influence of the global charge of the modified ODN on its binding to single -and double- stranded DNA is assessed by polyacrylamide gel electrophoresis and melting temperature measurements. Preliminary experiments showed that addition of positive charges has a clear stabilizing effect on small oligonucleotides duplexes. We are currently evaluating the biophysical properties of these new conjugates to assess DNA strand invasion, the next step towards gene correction.
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